Design and calibration of pulsed vapor generators for 2,4,6-trinitrotoluene, cyclo-1,3,5-trimethylene-2,4,6-trinitramine, and pentaerythritol tetranitrate

Computer-controlled pulsed explosive vapor generators for 2,4,6-trinitrotoluene (TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), and pentaerythritol (PETN) were built and calibrated to support an independent validation and verification facility for explosive detection systems for the Federal Aviation Administration at the Idaho National Engineering Laboratory. The explosive vapor generators will be used as quantitative vapor standards to establish the lower limits of detection of explosive detection systems. The generators were constructed using pure explosive suspended on quartz beads which were then loaded into a stainless steel tube. The tube was coiled and placed into a temperature-controlled chamber. A carrier gas (ultrapure air) was passed through the coil to carry the explosive molecules. The generators are capable of delivering a pulse of varying explosive mass through the control of coil temperature, airflow rate, and pulse width. Preliminary calibrations have been completed in the picogram to nanogram range using an ion mobility spectrometer as the calibrating instrument. 8 refs., 5 figs., 6 tabs.